On the streets of Midtown East, the burning questions are about Mayor Michael Bloomberg’s rezoning proposals intended to spur investment, redevelopment and growth among the neighborhood’s prewar buildings, most of which are more than 70 years old. Inside Grand Central, meanwhile, planners are already debating ways to ensure that the station will be capable of handling a growing burden of pedestrians, commuters, gawkers and passersby.

Among the options being considered:

A new stairway down to the Lexington Avenue subway, across the corridor from the existing escalators at 42nd Street, to help relieve a persistent problem with crowding at rush hour.

Reconfigured platforms for the Nos. 4, 5 and 6 trains, shrinking the footprint of staircases and providing greater breathing room on the system’s most crowded line.

A new connection from the existing lower-level tracks that would link the future station concourse of the Long Island Railroad to Metro-North, around an out-of-use underground track and directly into the mezzanine of the subway station (shown in the drawing above).

None of those proposals are underway yet. As with other items on the MTA’s wish list, they are dependent on a battle that is at its earliest stages. A new capital plan for the agency will eventually set out what projects get built over the next five years and how much the MTA devotes to each of them.

But Metro-North officials, who are in charge of Grand Central, are eager to press ahead with improvements to their prized station if they can find a way to pay for them.

The new 42nd Street stairway and the possible lower-level connection to the subway would help to solve “one of the major bottlenecks of the terminal,” Metro-North President Howard Permut said — a reference to the perennial jam-up at the top of the stairs and escalators that lead down to the Nos. 4, 5, 6, 7 and Times Square Shuttle trains near Grand Central’s southeast corner.

The new demands on the station will grow with the city, which is expected to add 1 million residents by 2030, and with the approval of the Bloomberg zoning proposal, which could add thousands of new office workers to the neighborhood.

But beginning work on those future projects — should the MTA even decide to undertake them — will require money.

The Department of City Planning’s studies of potential rezoning envision a new pool of “district improvement” funds — money paid by developers who want to build higher, which would be earmarked for pedestrian network improvements. In its most recent review of the zoning plan, the department explicitly cites the reconfigured subway mezzanine and new “connections between Grand Central Terminal and subway station” as possible enhancements.

The local community has responded with skepticism about the pace and planning of such improvements. Neighbors want to see immediate infrastructure improvements to accommodate existing conditions at the station, said Raju Mann, the transportation committee chairman of Community Board 5. He doesn’t want to wait until “after the buildings get built.”

But for the MTA to act on its own, it would need funding for new capital work. One official said the lower-level connection from LIRR and Metro-North to the subway could cost between $50 million and $100 million.

That’s a problem right now, the official added, because “there’s no money.”